#include "stdio_impl.h"

/* The behavior of this function is undefined except when it is the first
 * operation on the stream, so the presence or absence of locking is not
 * observable in a program whose behavior is defined. Thus no locking is
 * performed here. No allocation of buffers is performed, but a buffer
 * provided by the caller is used as long as it is suitably sized. */

int setvbuf(FILE *restrict f, char *restrict buf, int type, size_t size)
{
    f->lbf = EOF;

    if (type == _IONBF) {
        f->buf_size = 0;
    } else if (type == _IOLBF || type == _IOFBF) {
        if (buf && size >= UNGET) {
            f->buf = (void *)(buf + UNGET);
            f->buf_size = size - UNGET;
        }
        if (type == _IOLBF && f->buf_size)
            f->lbf = '\n';
    } else {
        return -1;
    }

    f->flags |= F_SVB;

    return 0;
}
